Extreme heat advisory hits Chicago on July 27, 2026

Heat advisories and an extreme‑heat warning were issued for the Chicago area on Monday, July 27, 2026. Forecasts called for heat‑index values exceeding 110 °F in western counties and over 100 °F elsewhere, prompting alerts for DeKalb, Grundy, La Salle, Livingston, Boone, Cook, DuPage, Kane, Kendall, Lake, McHenry, Will and several Indiana counties.

Meteorologist Tracy Butler warned that, while severe‑weather models show a low chance of storms, the high humidity could still spark rapid thunderstorm development. The city opened cooling centers at parks, libraries, police stations and senior centers, and urged residents to use 3‑1‑1 for well‑being checks.

Overall, the heat wave brought a Level 3 severe‑weather risk, prompting public health guidance and community resources to protect vulnerable populations.